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Again, the concept of a "Grand Tour" Voyager-Style relies upon simply doing fly-bys of the planets in question for gravitational assist, rather than actually stopping in orbit and doing some landings/research.  Otherwise, the propulsion and time requirments become prohibative.  I suspect we could build another mission around these lines if we wanted to, but really what is the point?  A simple fly-by is going to recover alot less data than a dedicated mission, and will cost as much if not more.

To me the real potential of planetary allignments that make Grand Tour style missions possible is to use those gravitational assist to send probes out to explore the limits of our solar system (helipause and what not).

GCRN's right after propulsion, reliability is the #1 problem for an interstellar spacecraft.  Face it, we have a VERY hard time building things right now that can last for 50+ years.  Much less a century or more.

In my view, some sort of hibernation for the spacecraft only makes sense.  If we are still talking about the mirror driven solar salior I was talking about before, than there really isn't anything for the craft to DO for all that time it spends in deep space.  Interstellar void is just that, void.  There really isn't anything intresting that we would want the probe to look at untill it starts to get fairly close to it's destination.  So having sensors and electronics on and transmiting data back realy doesn't make any sense, and would add enormous amounts of mass.  And communication to the craft is likewise pointless since the solar sail would have no ability to manuver untill it began to reach it's destination, and it's ability would be limited even then.

Now if we are talking about a more conventional probe, powered by a high-tech fusion engine, the answer becomes much simpler.  The engine will have to fire for a signifigant portion of it's journey, during which it will have ample excess energy to spend on heating, sensors, and communication.  Keeping such an engine "idling" during the transit would not consume a great amount of fuel in comparision to the amounts it would spend during the propulsive parts of it's mission.

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As for how to acomplish a hibernation, well I have no easy answers to this.  But since we are no where near ready to build an interstellar probe, we have some time to solve the issue.  However, I think solar power will have to be used to some extent, since it is the only power source we have that will be able to able to go from passive to active and warm up other more powerful sources, such as a nuclear reactor.

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Another issue is the targeting of the probe.  If hitting a target inside our system is difficult, hitting another STAR is quite several orders of magnitude more difficult.  Stars move as well you know, some quite rapidly.  LHS 52 is approaching us at ~300km/s.  Any stellar probe, which most likely can only manuver during the opening stages of it's journey, may have a hard time indeed hitting such a distant target.

I think you misunderstand my position.  It's not that I belive or disbelive in intellegent life on other planets/stars, its that I do not think we have enough information to make an intellegent guess on this issue.  Specificly, the drake equation which uses a number of variables to attempt to calculate the number of intellegent species in our galaxy (and alternativly the number that should be communicating with us) is useless because the fudge factor is so great.

There are millions of species, yes.  But apparently life only arrose once from non-life, and all of these millions of species developed from it.  How exactly this happened is still unknown, and we have not been able to duplicate it.  Thus we can't realy estimate the probability of it happening.

Although to be fair, we aren't entirely sure if life arose from life one time or multiple times here on Earth.  It seems that all current life traces back to a common ancestor, but we realy aren't sure.  We simply don't know.

Entirely my point.  Without more examples we cannot begin to estimate the probability of this happening.  Life could be the norm, or just a fluke.  One example is not enough to develop a good picture of the situation.

Also, we only assume that there are trillions of planetary bodies out there.  So far the only Earth like ones we know of are the ones circling our sun.  The other planets we have discovered have all been massive gas giants.  Planetary theory leads us to belive that their SHOULD be material left over for the formation of Earth like planets, but we have only one example to back this theory up.  Again, we simply don't know enough.

As for your other points Dook, I again think you have misunderstood my position.  I can undestand the philsophical argument that our vast universe should have life to fill it.  But there is no conclusive suport for that from a scientific point of view.  Just as science has no support for the existance of a soul.  These are philsophical/faith based positions, and while there is nothing wrong with that, science does not support them.  They are matters of belief or faith.

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Good point Rxke, but I still think it only strengthened my point.  Neanderthals did not survive to create a modern civilisation.  So it is not necessarily assured that a semingly intellegent species will do so.  They may be driven out before they can acomplish it.

I think intellegence may very well be extreamly rare in evolutionary terms.  It's certainly not a common adeptation.  Flight has been evolved multiple times (birds, insects, reptiles, bats), as have aquatic adeptations.  But intellegence has only apparently been adapted once.  Perhapce it is not very common, or maye it does not give a species a very big advantage in survival, but in any case it has proven to be the exception not the rule on Earth.

The only problem then, is trying to stop.  You would be going way to fast to safely aerobreak into Martian orbit.  So at least some propulsive breaking would be necessary.  And for the Jupiter mission, I don't think the crazies would be happy with a Nuclear Engine starting up so close to Earth's atmosphere, but then again, we don't have to tell them do we.  Since the exhaust would all be moving at a greater than escape velocity, it shouldn't be to much of an issue.

My problem with the Drake Equation is that many of it's terms are complet guesswork.  We have a very good idea how many stars are in our galaxy, and a somewhat poorer understanding of what percentage of these stars could possibly have Earth like planets (F, G, and K primarily.  And an even poorer idea as to what percentage of the starts in these classes could actualy have habitabl planets (ie. solitary, population I stars, w/out brown or white dwarfs in close orbit).  Our ideas about the percentage of planets on this fraction is based mostly on theory and guesswork, and basicaly all the rest of the variables are just wild guesses. 

We have no real idea what the chances of life evolving are, or what the chances are of that life evolving into complex orginisims.  Rember life on Earth stayed very primative for billions of years before complex orginisims started to arrive.  Guesses as to what fraction devlopes a recognisable intellegance and what fraction actualy attempts to communicate, have no basis in fact.

This combines to make the Drake Equation useless IMO.  Without sound estimates for the unknown variables (which we currently lack) life in the Galaxy could varry from millions to just us.

The problem with this is that even a massive deployment of nuclear weapons of woudl not posess enough energy to remove a signifigant quantity of Venus's atmosphere.  Indeed the explosion of a nuclear-warhead, say 100MT would be childs play in comparision to the amount of solar energy Venus recives every secound.

Venus has a radius of ~6200km giving it a reflective area of ~113 million kilometers.  It's solar irradiance is about 2600 w/m^2 meaning that every secound, about 300 BILLION megajoules of energy irradiate the surface.  A modest 10 megaton nuke only puts out about 40 billion megajoules, so Venus is receiving about 8 times as much energy every secound.  Since the Suns energy is not enough to drive off Venus's atmosphere (though it comes pretty close) even mass deployment of large devices is unlikely to affect it.  No, if you want to blast off Venus's atmosphere, you have to think bigger, like large fast moving asteriod impact bigger.

Chemical explosives fare even worse.  Even Hydrogen and Oxygen, one of the most potent explosive combinations possible, has an energy density of only ~13MJ/kg.  This is about 3 times greater than TNT, but several orders of magnitude worse than nuclear weapons.  Indeed, chemical explosives probably don't contain enough energy in them to overcome Venus's gravity at all, so you would be adding to the already thick atmosphere, not reducing it.

Of all the ideas talked about here (on this form I mean) I like the concept of driving off the atmosphere with a large lense/mirror and the asteriod impact concept the best.  Maybe if they were used in concurt we could actualy achive somethign.

Do you have an alien encounter story you wish to share with us?

I know I should usually ignore trolls, but you dued have seriously lost it.  You should seek help and get away from the keyboard, seriously.  Accusing random people on the internet of being members of the Skull and Bones society?  You give us to much credit, we are the normal every-day kinds of jerks, not the world dominating secret society having kind...

Or are we  8)

Seriously though, seek some help man, you are seriously delusional and paranoid.  And these webforms are just feeding into that problem.  They have some really good medications now that can help.

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On another note, the admins should just ban him and his 4+ alter egos.  For his own good.

I appreciate your effort, but frankly, I'm still going to have trouble telling the two VTTFSH_? with two stars pictures appart.

Ah, my mistake.  In this case the figure of $500 Billion for 5 GW ($1000/kw) is completely loony.  I'll do some quick math to prove it.  Launch costs right now might get down to about $5,000/kg for unmanned cargo launches to LEO.  Your SPS needs to by higher than that, but lets assume you have a fleet of them or what not, or some fancy LEO-GEO tug and so can avoid this cost.  Advanced solar panels might be able to get 75 W/kg, but lets call it a nice even 100 W/kg to make the math easier and to provide some room for further advancment.  So at $5000/kg to LEO and 100W/kg we get an astonishing cost of $50,000/kW.  50 times greater than your figure, which was only just barely supperior to nuclear and coal fuel already (and inferior to Gas I might add).  And this is with some VERY generous estimations in your favor.  Since lots of costs, such as the support structure for the SPS, or the recivers on Earth, or the design and construction of this massive behmoth are omitted.  Far from the ~$100 Billion dollar Apollo Program, you couldn't fit such a program inside the capital budget of the US, period.

This comment was made in jest in reply to your "friends" point that "Many areas of Earth lack fertile soil."  Making empty space look attractive in the alternative I suppose.  My point (which you do not quote, but I elaborate on further down) was that reclaiming currently unproductive land on Earth will ALWAYS be more cost effective than manufacturing it or "Terraforming" it elseware.  Period, end of story.  There is no NEED to "Terraform" Antarctica, because it is ALREADY part of the Earth.

Again, as was the main theme of my arguments here is that we (and Dook as well I susspect) are not realy in disagrement on these issues, except on the point of time frame.  Since Colonization can never be cost effective in the traditional sense, it must return some non-montary justification.  And while I (and most others I suspect) agree on the benifit of these other justifactions, we don't see them as being worth there extravigant cost in the short term.  Right now it simply costs to much and the ephemeral returns it gives are not enough to justify it.

I STILL favor expaditions to Mars and a permanate presence there.  But colonization, especialy the many 10,000 people models people fantisise about.  Will have to wait untill technology advances, and our civilisation gets richer, making these things affordable.  I think that is all Dook has ever realy tried to say.

Again we are not so much in direct disagrment.  I agree with the point of an extra-terrestrial colony serving as a shield against disaster, I just do not see it as a something we can realisticly accomplish very soon.  But even then preventing the disaster (I'm assuming you mean an asteroid impact or something) is still far more cost effective than colonisation.  And even if we DO colonise Mars, does this mean we just sit there and let Earth get hit?  Of course not.  We do both.  This is an example of a "false dilemma."  Our options are not simply colonise or die, with or without Mars as a safety net, saving the Earth is the most attractive.

Also, I dislike appeal to authority because it tends to lead people to make claims and arguments backed up by the weight of there supposed authority, that these authorities never realy made.  I can do my own RESEARCH and math just fine on my own thanks.  In this case however, I just happen to have a copy of Entering Space at hand, and I will compare it to your arguments.

A do not wish to compound my "appeal to authority" with an "ad homium" attack, but perhapce it is you who should do further study on these issues.

While I still can't see any conceivable reason to need to use He3, I'm glad we can at least somewhat agree on this matter.

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::EDIT -- Correct some quote errors::
I come of a little bit hotter here than I usualy do, but some of your little digs get to me.  I like and respect the majority of the people here.  You can be pretty much assured that we have all probably read the same books and papers, or else we wouldn't be here.  I usualy don't go for personal attacks or respond in kind, but this was little much for me, you got my old debaters blood rolling .  I'll try and keep it clean if you will.
::EDIT again, not enough sleep lot more spelling/grammer errors than usual, even for me.

After futher thought, I realy shouldn't have posted in that other thread.  Isn't this that same nut that keeps showing up around here?  I rember him starting a couple of threads a month or so ago under the name ISA or something.

We should just ignore him/her 

I think GCRN responds well to most of this, but I take issue with this point.  Sure the diffrence in relative velocity of Earth and Mars is not that great when compared to other quantities, such as the planets orbital velocity or even the energy need to enter orbit.  And thus the necessary Delta-V may seem deceptivly small when compared to these figures.

However, that does not change the fact that a diffrence of 2-5km/s bettwen a object in a normal Earth/Mars orbit and a Cycler on it's free return orbit is alot.  A heck of a lot.  In some of the better case senarios we are talking about a diffrence of like Mach 15 in speed, some 18,000 kph or 11,000 mph.  This is REALY fast.  The fact that this diffrence is speed is small in comparison to the orbital velocity of the planets is inconsiquental.  You can't dock at these speeds, it's not even close to possible.  You MUST match velocity with the cycler, and this takes about the same amount of fuel as it would to go to Mars in the first place.

GCRN disccused the amount of fuel necessary for an abort option, but realy it's not practicle.  That same amount of fuel could send you to Mars and back.  So realy your only options are Dock or Die.

I stand by my earlier analogy, it's like trying to board an airplane by being fired out of a cannon.

One of the best things that could happen to the world space programs is for Energia to be re-activated.  I think we are all in pretty much in agrement, it was the best HLLV that was ever developed.  If the Russians are so hell bent on finishing ISS, I say they should go for it.  Energia+Progress certianly makes a hell of a lot more sense than Shuttle + anything.

That said, I don't think we should pay for it.  We should keep our money here as much as possible.  Furthermore, it's pretty much political reality that the US funding the Russian Energia probably isn't going to happen, no matter how great it is.  The HLLV we have on the drawing board right now could be pretty potent in it's own right.  The shuttles engines and the solid boosters are both pretty rock solid incredible technologies in their own right.  My only worry is that it doesn't appear to have the same ability to scale up that the Energia does, as adding more SRB isn't going to improve its performance that much.

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I agree that the ISS could potentialy be a good test-bed for the necessary long duration LSS tests we are going to need.  However, the rest of the station is pretty much a flop.  I don't think that the necessary test for the LSS system are enough justification to continue the station.  Building the ITV (or whatever we are going to call them) and testing them in Earth orbit makes alot more sense to me.  We could do a couple months/years cycling around the Earth and Moon for example.  Or build the space staion ouf of them GCRN talked about.  Our moon program should test the Hab side of things as well.

But while I am talking about political realities, it looks like ISS is going to go forward no matter how little sense it makes.  So we (the Mars Society) should definetly push for the appropriet LSS modules to be sent up.  I belive they are currently scheduled to be cut.